Semester of Graduation
First Major Professor
Dr. Andrew Lenssen
Master of Science (MS)
Nitrogen is an abundant element important to many aspects of life as we know it. In plants, nitrogen is an essential macronutrient and is required by many agronomic crops, including soybeans [Glycine max (L.) Merr.], for multiple functions related to plant growth and development. Although abundant in the atmosphere, nitrogen uptake and utilization in plants is complex requiring nitrogen to be altered into forms available for plant uptake and assimilation. Legume crops, like soybeans, are able fix nitrogen from the atmosphere and utilize it for plant growth and development. However, as yields continue to increase in soybeans, the need for additional nitrogen might be necessary. This study was designed to evaluate the effectiveness of adding additional nitrogen to soybeans during the R3 growth stage.
Research was conducted in west central Missouri near Richards, Missouri. The study was a single-year study conducted in 2017 and was executed in a replicated strip-strip trial design. The study incorporated two other components in its evaluation as well, multiple soybean varieties, ranging from a 4.5 maturity group to a 4.9, as well as plant densities. Three different soybean varieties were planted at two different plant densities, 150,000 and 170,000. Each variety by density combination was left untreated, treated with 30 lbs/acre of nitrogen and lastly treated with 60 lbs/acre of nitrogen. Urea was the source of nitrogen utilized in this study.
Yield was significantly different between the three varieties utilized in this study. In addition, the three-way interaction of density by nitrogen rate by variety was also significantly different in yield. At the higher plant density, the two later maturity varieties, yielded an average of over 4.5 bushels per acre better with 60 lbs per acre of nitrogen compared to the untreated control. At the lower plant density, no significant yield difference existed for any variety between either nitrogen rate when compared to the untreated control. In summary, at higher plant densities, this study concluded that later maturity varieties yielded more with an additional 60 lbs of nitrogen per acre applied as urea treated.
Buesing, Ben, "Soybean varietal response to late season nitrogen application at different plant populations" (2019). Creative Components. 376.